A snorkel device for a submarine is known where the snorkel tube is able to be extended out of the tower of the submarine and retracted again. An optical periscope is assembled in a guided manner in order to observe the sea region above the water during the submerged travel of the submarine carried out at the so-called periscope depth (snorkel travel with which the snorkel tube is extended with the periscope). It is furthermore necessary to separately extend an antenna mast with an antenna means in order to permit communication, in particular radio communication, with other communication participants at sea. For this, the respective antenna is arranged at the upper end of a long mast which is extended out of the tower of the submarine by way of a long-travel cylinder, and is retracted again after the radio communication has been effected.
If the snorkel and the antenna means or several antenna means are extended, the speed of the submarine is reduced on account of the considerably increased resistance of the water on all the extended apparatus, by which means in turn the fuel consumption for the combustion motor drive of the submarine increases. Furthermore if the snorkel with the periscope and one or more antenna masts are extended, a large so-called signature, i.e. a white water tail of water foam and sea spray in the form of a bow wave are formed trailing on the surface of the sea from the extended apparatus, which is or are very easy to recognize and therefore permits an unambiguous, but undesirable location of the submarine. A mutual hindrance of the functioning is also the case when several antenna masts are extended. This is particularly the case with the periscope, whose viewing function is limited by the extended masts.
Furthermore by way of combined construction of the snorkel and the periscope extending axially in the inside of the snorkel and guided through the pressure hull of the submarine, only a limited positioning of the periscope is possible with regard to space, i.e. in particular of its lower end in the inside of the submarine. Furthermore the periscope may only be used in its completely extended condition because its viewing optics which are provided at the lower end of the periscope are only then located at the eye height of the operating persons concerned.